The present invention concerns a plug-in coupling for pressure application systems, consisting of two coupling components, namely a receiving component and a connector component, whereby the connector component can be inserted into a locating opening of the receiving component in a direction of insertion with a connecting shaft sealed around the perimeter, and can be arrested against loosening by a holding element situated in a recess of the one connector component firstly in a partially inserted, incompletely sealed pre-lock position, and secondly in a fully inserted perfectly pressure sealed full lock-in position.
Such types of plug-in couplings are used in motor vehicle braking systems for example, especially for pneumatic braking systems. Among others, one such plug-in coupling has been proposed for this purpose by the applicant in the German patent application DE 196 21 535. To prevent a faulty assembly which could induce a separation of the coupling under pressurization and which was not initially noticed, this plug-in coupling guarantees a "pre-locking", which prevents a complete separation of the coupling under pressurization in the not quite perfectly inserted state of the coupling components. This includes provision for a desired leakage in this pre-lock position. Upon pressurization, this state can be acoustically noticed by a leaking sound, without nevertheless leading to a complete sudden pressure drop. When the leaking sound occurs, the coupling can be transferred farther into the properly sealed and arrested "full lock-in position."
The plug-in coupling proposed in DE 196 21 535 particularly distinguishes itself in that the holding element cooperates with one and the same locking edge both in the pre-lock position and the full lock-in position. The holding element preferably consists of one bracket situated in the recess of the one coupling component and two arresting elements, which are clamped elastically deformable in the bracket and axially arranged one behind the other, whereby the first arresting element engages behind the second coupling component's locking edge in the pre-lock position, and the second arresting element engages behind it in the full lock-in position.
The proposed plug-in coupling is easy and inexpensive to manufacture and has been proven in actual assembly. It has nevertheless demonstrated that there is still room for improvement regarding the security of the plug-in connection during operation, particularly regarding this connection's stability under the influence of pressure variations in the working medium or of vibrations.
It is therefore the objective of the present invention, proceeding from the stated state of the art, to create a plug-in coupling which attains still higher security during pressure variations and vibrations which occur, without losing the coupling's advantages in assembly. In particular, this objective consists of improving the plug-in coupling proposed in DE 196 21 535 with the idea of yet higher dependability.
In accordance with the invention, this is attained by a plug-in coupling for pressure application systems consisting of two coupling components, namely a receiving component and a connector component, whereby the connector component can be inserted into a locating opening of the receiving component in a direction of insertion with a connecting shaft sealed around the perimeter, and can be arrested against loosening by a holding element situated in a recess of the one connector component firstly in a partially inserted, incompletely sealed pre-lock position, and secondly in a fully inserted perfectly pressure sealed full lock-in position, whereby in the two lock-in positions, arresting elements of the holding element each engage behind a locking edge of the other coupling component when a lock-in connection is formed, and whereby the holding element is designed and arranged relatively movable in the recess of a coupling component in such a way, that, at least in the full lock-in position, at least one arresting element, by shifting the holding element against the direction of insertion, can be transferred into a locked position, in which the release of the lock-in connection is prohibited through interlocking, from an unlocked position in which the lock-in connection can be released.
The manufacture and assembly of the plug-in coupling in accordance with the invention is not only very simple here, but a higher dependability and reliability of the lock-in connection(s) is attained in accordance with the invention in the full lock-in position (and optionally even in the pre-lock position).
In contrast to the subject of the proposed plug-in coupling with a stationary "double-locking" holding element, this holding element, in the case of the invention, is arranged mobile in the recess, in an axial direction in particular. The recess is preferably designed as an inner ring groove within the receiving component. At least one latching section, which is arranged stationary to the recess and which cooperates with the arresting element, can be provided for positive prevention of the release of the lock-in connection.
There are various possibilities for the structural arrangement of a latching section: for example, the latching section can be a component of the coupling component which contains the recess. But it can also be a component of a separate latching part arranged in the recess, especially a ring part, whereby an improved ability to disengage during disassembly of the plug-in coupling can be attained.
The positive locking of the lock-in connection's disengagement, by transferring the arresting elements from the unlocked into the locked position by shifting the holding element, can be provided with advantage, as previously mentioned, both in the full lock-in position and in the pre-lock position.
Other advantageous characteristics of the invention are contained both in the dependent claims and in the following description.